如何在R语言中从数据集中删除多个指定日期？

我能使用filter从数据集中删除单个日期，但找不到删除多个日期的方法。以下是我的数据集及尝试的代码，两种方法均未生效：

a <- structure(list(year = c("2011", "2011", "2011", "2011", "2011", 
"2011", "2011", "2011", "2011", "2011", "2012", "2012", "2012", 
"2012", "2012", "2012", "2012", "2012", "2012"), month = structure(c(8L, 
8L, 9L, 9L, 10L, 10L, 11L, 11L, 12L, 12L, 8L, 8L, 9L, 9L, 10L, 
10L, 11L, 11L, 12L), .Label = c("January", "February", "March", 
"April", "May", "June", "July", "August", "September", "October", 
"November", "December"), class = "factor"), sixteen = structure(c(15187, 
15203, 15218, 15234, 15248, 15264, 15279, 15295, 15309, 15325, 
15553, 15569, 15584, 15600, 15614, 15630, 15645, 15661, 15675
), class = "Date")), class = "data.frame", row.names = c(NA, 
-19L))

# 数据集预览
year     month    sixteen
1  2011    August 2011-08-01
2  2011    August 2011-08-17
3  2011 September 2011-09-01
4  2011 September 2011-09-17
5  2011   October 2011-10-01
6  2011   October 2011-10-17
7  2011  November 2011-11-01
8  2011  November 2011-11-17
9  2011  December 2011-12-01
10 2011  December 2011-12-17
11 2012    August 2012-08-01
12 2012    August 2012-08-17
13 2012 September 2012-09-01
14 2012 September 2012-09-17
15 2012   October 2012-10-01
16 2012   October 2012-10-17
17 2012  November 2012-11-01
18 2012  November 2012-11-17
19 2012  December 2012-12-01

# 定义要删除的日期
days <- c('2011-12-17', '2012-12-01', '2012-11-17')

# 尝试的两种无效方法
subset(a, !as.Date(sixteen) %in% days)
a[!(a$sixteen %in% days),]

问题根源 #

你的代码失效的核心是数据类型不匹配：sixteen列是Date类型，但days是普通字符向量，%in%运算符无法在不同类型的向量间完成正确匹配，导致筛选逻辑失效。

有效解决方案 #

方案1：统一日期类型 #

将days转换为Date类型，再使用你原来的写法即可生效：

# 转换days为Date类型
days <- as.Date(c('2011-12-17', '2012-12-01', '2012-11-17'))

# 方法一：subset筛选
result_subset <- subset(a, !sixteen %in% days)

# 方法二：索引筛选
result_index <- a[!(a$sixteen %in% days),]

方案2：使用dplyr的filter（tidyverse风格） #

如果你习惯使用tidyverse工具链，用filter函数结合类型转换可以更直观地完成筛选：

library(dplyr)

result_dplyr <- a %>%
  filter(!sixteen %in% as.Date(c('2011-12-17', '2012-12-01', '2012-11-17')))

结果验证 #

执行上述任意一种方案后，原数据集中的第10、18、19行（对应三个要删除的日期）会被成功移除，最终得到包含16行记录的数据集。

内容的提问来源于stack exchange，提问作者Salvador